Zhang Danyu, Yang Shiwei, Cheng Heyong, Wang Yuanchao, Liu Jinhua
College of Material Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, China; Key Laboratory of Organosilicon Chemistry and Material Technology, Hangzhou Normal University, Hangzhou 311121, China.
College of Material Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, China; Key Laboratory of Organosilicon Chemistry and Material Technology, Hangzhou Normal University, Hangzhou 311121, China.
Talanta. 2019 Jul 1;199:620-627. doi: 10.1016/j.talanta.2019.03.023. Epub 2019 Mar 2.
Multi-elemental speciation analysis in a single run reduces costs, waste and time, and also sample consumption, which is favorable to a large set of instable samples. This work demonstrates mercury and arsenic speciation in a single run using high performance liquid chromatography with inductively coupled plasma mass spectrometric detection (HPLC/ICP-MS). Thiol compounds in mobile phases interfered with the elution of arsenite because of coordination action, which was overcome by gradient elution (elution of As(III) by thiol-free mobile phases at first). Four arsenic forms (As(III), DMA, MMA and As(V)) and three mercury species (Hg(II), MeHg and EtHg) were separated and detected by HPLC/ICP-MS using 4 mM tetrabutylammonium hydroxide (TBAH) (pH 6.0) in the first 1.0 min and 4 mM TBAH + 20 mM L-cysteine (pH 6.0) in the next 9.0 min. The detection limits were obtained at 0.078 for As(III), 0.081 for DMA, 0.078 for MMA and 0.15 μg L for As(V), and 0.016 for Hg(II), 0.027 for MeHg and 0.032 μg L for EtHg, and the reproducibilities (50 μg L for each As-species and 10 μg L for each Hg-species) were all lower than 3.7%. The proposed method was successfully applied for speciation analyses of arsenic and mercury in five lotus roots, which indicated DMA (3.5-7.9 μg kg) as the only arsenic species and MeHg (0.6-1.0 μg kg) as the only mercury species. Analyses of two certified reference materials demonstrated good agreement between determined values and certified values. All results prove its advantages including high sensitivity and high analytical efficiency, which are beneficial for routine speciation analyses of arsenic and mercury in a single run in environmental and food fields.
一次运行中的多元素形态分析可降低成本、减少浪费和时间，还能降低样品消耗，这对大量不稳定样品有利。这项工作展示了使用高效液相色谱与电感耦合等离子体质谱检测（HPLC/ICP-MS）在一次运行中对汞和砷的形态分析。流动相中的硫醇化合物由于配位作用干扰了亚砷酸盐的洗脱，通过梯度洗脱（首先用无硫醇流动相洗脱As(III)）得以克服。通过HPLC/ICP-MS分离并检测了四种砷形态（As(III)、DMA、MMA和As(V)）和三种汞形态（Hg(II)、MeHg和EtHg），在前1.0分钟使用4 mM氢氧化四丁基铵（TBAH）（pH 6.0），接下来的9.0分钟使用4 mM TBAH + 20 mM L-半胱氨酸（pH 6.0）。As(III)的检测限为0.078，DMA为0.081，MMA为0.078，As(V)为0.15 μg L，Hg(II)为0.016，MeHg为0.027，EtHg为0.032 μg L，重现性（每种砷形态50 μg L，每种汞形态10 μg L）均低于3.7%。所提出的方法成功应用于五种莲藕中砷和汞的形态分析，结果表明DMA（3.5 - 7.9 μg kg）是唯一的砷形态，MeHg（0.6 - 1.0 μg kg）是唯一的汞形态。对两种有证标准物质的分析表明测定值与认证值之间具有良好的一致性。所有结果证明了其具有高灵敏度和高分析效率等优点，有利于环境和食品领域中一次运行对砷和汞进行常规形态分析。
